This invention relates to a more commonly known as an apparatus for aspirating and discharging device for supplying a sample into a detecting cell such as a prismatic refractometer or an oscillating densitometer, and after the measurement discharging the sample from said detecting cell. And more specially it relates to a well-manipulating sample sucking-discharging device that can suck and discharge a high viscosity sample, in which the speed of the sucking and discharging of the sample can be adjusted easily and arbitrarily, and the sucking and discharging operation can be performed with facility by one hand and need not to press a piston at the time of stopping the operation.
In an oscillating densitometer composed of a U-shaped thin tube provided with a detecting cell called an oscillating cell, the density of a sample liquid is to be calculated according to the frequency of the oscillating cell when said cell is filled with the sample. The sample is introduced into the oscillating cell by sucking or pouring under pressure. In case there is an enough volume of the sample, the introduction continues for the specific time from the starting, and then stopped. In case there is a small volume of the sample, the sample extracted by an injector or a syringe is supplied to the oscillating cell by a sucking-discharging device, and after the measurement, it is drained away from said cell by the sucking-discharging device.
As shown in a block diagram in FIG. 12, a sample sucking-discharging device utilized for sucking and discharging a sample into the oscillating cell is composed of an injector, which comprises a cylinder 5a provided with a port at one end, a piston 5b installed in the cylinder 5a so as to move, and a spring 5c for pressing the piston 5b toward the bottom of the cylinder 5a, and in which the port 5d of the cylinder 5a is connected with an oscillating cell of the oscillating densitometer, that is, a detecting cell.
When a sample is extracted by using the injector 5, an operator presses the piston 5b with his finger to the bottom of the cylinder 5a, that is, a bottom dead position, and while a sample inlet of the detecting cell connected with the port is soaked into the sample, the power of his finger pressing down the piston 5b is gradually reduced and then the piston 5b pushed up by the force of the spring 5c sucks the sample into the cylinder 5a. 
And as shown in a block diagram in FIG. 13 the above apparatus is available for the sucking and discharging of a sample to an optical cell of the prismatic refractometer.
In the above injector 5, the force for sucking a sample into the cylinder 5a depends on the elastic force of the spring 5c, so that it sometimes occurs that a high viscosity sample cannot be sucked. In order to suck up the high-viscosity sample, the spring 5c must be powerful. But in case of sucking a low viscosity sample such as an organic solvent, for example, the usage of the powerful spring 5c increases the speed of the sucking too much. As a result, the condition under exceedingly reduced pressure is generated; accordingly it may occur that the measurement is conducted under the condition that the sample includes small bubbles. Specifically, since the force of sucking a sample into a cylinder 5a of the injector 5 depends on the elastic force, the sucking speed cannot be meet with the sample characteristic, and the sucking time cannot be adjusted for a specific volume of sample. And in case of stopping the sucking not so as to suck the air after the sample sucking, it is necessary to stop the moving of the piston 5c by supporting with the finger. Those points are demerits in order to improve the manipulation of the apparatus.
There are also the same problems in case of using a syringe. In the injector not including a spring 5c, the piston 5b needs to be pulled up by hand and the one-hand operation cannot be carried out. Therefore, the manipulation is worse.
The present invention can solve the above-mentioned problems and the objects of the invention are to provide a well-manipulating sample sucking-discharging device that can suck and discharge a high viscosity sample, in which the speed of the sucking and discharging of the sample can be adjusted easily and arbitrarily, the sucking and discharging operation can be performed with facility by one hand, and need not to press a piston at the time of stopping the operation.
In order to achieve the above object, the present invention presupposes a sample sucking-discharging device which comprising an injector provided with a cylinder and a piston installed in the cylinder so as to move up and down; a main body for holding the cylinder of the injector; a gear or a pair of gears held in the main body so as to rotate on an axis right-angled to the moving direction of the piston; a first rack, of which one end is connected with the piston, for moving with meshing with the gear or the pair of gears; and, a second rack held in the main body so as to move in the direction opposite to or crossing with the moving direction of the first rack while meshing with the gear or the pair of gears.
The injector may adopt a well-known product comprising a cylinder made from synthetic resin or glass, and a piston installed in the cylinder so as to move up and down. And it is also possible to make up one unit by combining the cylinder and the following main body.
The main body holds one gear or a pair of gears and the second rack other than the cylinder of the injector, and also holds the piston and the first rack via the cylinder. To stabilize the operation of the first rack, the first rack can be held directly by the main body.
The shape of the main body may be formed so as to hold the cylinder of the injector, the gear or the pair of gears and the second rack. It""s preferable to consider the manipulation and the design. Specifically, the main body may be formed in a cylindrical form or an oval-cylindrical form, for example. And the material of the main body is not limited specially, but may adopt a resin, a metal, a glass and etc.
The gear or the pair of gears is held by the main body at the specific position toward the cylinder of the injector so as to rotate on an axis right-angled to the moving direction of the piston, and then may mesh with the first and the second rack.
In the invention, the main body holds the gear or the pair of gears, which includes one gear comprising a hub and plural teeth formed in a line around the hub, and a dual gear comprising a hub and plural teeth formed in two lines around the hub. In case of the former, the first and the second rack are arranged to mesh with the teeth formed in a line. And in case of the latter, the first and the second rack are arranged to mesh with the different line of the lined teeth respectively.
The kinds of the above-mentioned gears are not restricted particularly, if the gears can mesh with racks (teeth line) the weight formed in the first and the second rack, or with diagonal racks. And it is possible to use a spur gear of which the teeth in a straight line is cut in parallel with the axis, a helical gear of which the teeth line is twisted in diagonal to the axis, or a herringbone gear that two helical gears facing on the opposite direction each other adjoin on the same axis. But it is arranged in the invention that a common gear may mesh with both racks, so that the construction can be the simplest. And said construction can adopt the spur gear as a gear, therefore, there is a merit that the cost can be reduced.
When the invention adopts a pair of gears, it is arranged that the two gears be connected with each other so as to rotate synchronously in the same direction respectively, and the first and the second rack mesh with each different gear.
In the first rack of which the end is connected with the piston of the injector and which moves while meshing with the gear or the pair of gears, the axis direction of the first rack is positioned in parallel with the moving direction of the piston and so as to move in the axis direction.
It is not necessary to provide with means for guiding the move of the first rack in particular, but in order to stabilize the move of the first rack and to mesh it with the gear or the pair of gears accurately, it is preferable that guiding means for guiding the move of the first rack may be provided in the main body.
The second rack is held in the main body so as to move in the crossing direction or the reverse direction to the moving direction of the first rack while meshing with the gear or the pair of gears.
When the second rack is held in the main body so as to move in the direction reverse to the moving of the first rack while meshing with the gear or the pair of gears, a discharging button is provided at one end of the first rack that is connected at the other end with the piston, pressing the discharging button presses down the piston to the bottom of the cylinder via the first rack, and then the sample in the injector is discharged by the piston.
Also in this case, when a sucking button is provided at one end of the second rack that is the same side as the discharging button, pressing the sucking button pulls up the piston to the upper side of the cylinder via the second rack, gears, and the first rack moving in the direction reverse to the second rack, and then the sample is sucked into the injector.
When the second rack is held in the main body so as to move in the direction crossing with the moving direction of the first rack while meshing with the gear or the pair of gears, a discharging button is provided at one end of the second rack, while a sucking button is provided at the other end of the second rack, pressing the discharging button presses down the piston to the bottom of the cylinder via the second rack, the gear or the pair of gears, and the first rack; on the other hand, pressing the sucking button pulls up the piston to the upper side of the cylinder via the second rack, the gear and the first rack.
And in this case, when the apparatus comprises a gear composed of dual gear provided with teeth in a different radius formed in two lines, a gear in small radius and pitch is meshed with the first rack, and a gear in large radius and pitch is meshed with the second rack. Thereby, the operation of the first rack can become more powerful than that of the second rack, that is, it is possible to strengthen the operating power of the piston of the injector. The sucking of the more high viscosity sample becomes easy. The operation amount of the first rack gets to be less than that of the second rack. Therefore it is easy to perform the fine adjustment of the sucking speed for the sample.
By using a pair of gears in a different radius, a gear in small radius and pitch is meshed with the first rack, while a gear in large radius and pitch is meshed with the second rack, so that the same effect can be obtained.
When the second rack is held in the main body so as to move in the direction crossing with the moving direction of the first rack while meshing with the gear or the pair of the gear, the pressing of the first rack can discharge the sample out of the injector.
Specifically, in case the second rack is held in the main body so as to move in the direction crossing with the moving direction of the first rack while meshing with the gear or the pair of the gear; a discharging button is provided at one end of the first rack that is connected at the other end with a piston; and a sucking button is provided at one end of the second rack, pressing the discharging button presses down the piston to the bottom of the cylinder via the first rack; and on the other hand, pressing the sucking button pulls up the piston to the upper side of the cylinder via the second rack, the gear or the pair of gears, and the first rack.
As described above, the invention is arranged that the operation of pulling the piston from the bottom of the cylinder to the port is equivalent to the operation of pressing the second rack by finger. If the power of the finger is stronger, even in case of the high viscosity sample, it is possible to suck the sample into the cylinder. When the speed of pressing the second rack is adjusted by finger, it is possible to adjust the sucking speed or the time of the sucking for the specific volume. Since there is not a spring that presses the piston or the rack, or an elastic membrane that enlarges the capacity of the syringe, even when the hand is released from the rack at the stopping of the sucking and discharging, it does not move the first and the second rack, the gear or the pair of gears, and the piston. Therefore, it will not occur that the sample turns back to the cylinder or that the air is suck into the cylinder. It is not necessary to press the piston at the stopping of the sucking and the discharging.
And both the pressing and the pulling operations of the piston can be performed by the pressing operation of the first or the second racks, for example, while holding the cylinder of the injector by the palm, the little finger, the ring finger, and the middle finger of hand, the thumb and the forefinger perform the pressing and pulling operations of the piston. Therefore, one hand operation can perform the sucking and discharging easily.
The piston of the injector may be connected with the one end of the first rack so as to link with each other, and a transmitting means may be arranged to intervene between the piston and the first rack, such as a rod, a lever and etc. that is able to transmit the operation bi-directional. But it is preferable that in order to improve the certainty of the operation, the first rack is directly connected with the piston via a holder provided at one end of the first rack.